Path: utzoo!attcan!uunet!samsung!zaphod.mps.ohio-state.edu!usc!ucsd!ucbvax!hplabs!hpda!hpcuhb!hpcilzb!dick
From: dick@hpcilzb.HP.COM (Dick Lucas)
Newsgroups: sci.electronics
Subject: Re: Battery Queries
Message-ID: <1310026@hpcilzb.HP.COM>
Date: 15 Mar 90 16:57:42 GMT
References: <32769@brunix.UUCP>
Organization: HP Design Tech Center - Santa Clara, CA
Lines: 7

Why not use deep cycle batteries for the +/- 12 volts? (one for each 
polarity)  For the 5 volt supply you can still buy 6 volt auto batteries.
Most 5 volt requirements have a 10% tolerance on them and you could drop
the required voltage with a large diode.  This may not be a very elegant
solution, but it would be cheap and easy to accomplish.  If you assume 
a full volt drop across the diode (or two) the efficiency of this method
is 83% which compares favorably with most switch mode power supplies.